This invention relates to a rolling platform device for assisting in writing, drawing, etc., and which may also be utilized by handicapped persons, as a teaching aid, and so forth.
Many devices have, in the past, been employed as a writing support, and these can be divided into two types. The first type of support includes a friction contact member that carries a pen, and which requires the user to move against the force of friction in order to produce a mark on a writing sheet. The second type of support employs a roller bearing device which reduces the friction between the user and a writing sheet.
Two typical patents of the roller bearing support device are described in U.S. Pat. Nos. 757,383 and 1,627,635. The former patent discloses a device having a single ball bearing in a grip type platform, and the latter patent describes a bearing race mounted in the platform. The writing support employing a bearing race is expensive and unnecessarily heavy. Also, due to its low friction properties, it manipulates too readily and hence, the user does not have complete control over the device. Finally, if erasures are made on the writing sheet or paper, erasure particles will eventually be picked up by the bearings and will ultimately jam the race. In the case of a writing platform employing a single bearing, the friction load is simply too great to enable ease of manipulation.
A writing device is required that is inexpensive and which enables the user to easily clean or replace a jammed bearing. Also, the device should provide the proper writing friction and should enable the user to write or draw effectively on an uneven surface.